NASA's Voyager 1 has reportedly left our solar system, according to a group of scientists from the University of Maryland (UMD) -- but NASA disagrees.

The UMD team -- led by Marc Swisdak, UMD research scientist; James F. Drake, a physicist at the University of Maryland, and Merav Opher, of Boston University -- have created a model that they claim proves the Voyager 1 has finally left our solar system and entered interstellar space.

In fact, the team believes Voyager 1 crossed into interstellar space July 27, 2012. But NASA researchers still don't believe Voyager 1 has done so.

How is there such a huge disconnect between both beliefs? On NASA's side of the situation, Voyager 1 has recorded erratic shifts in solar particle and galactic particle counts -- and at one point, solar particle counts disappeared while galactic particles remained, which would indicate an exit of our solar system -- but the lack of directional change in the magnetic field makes NASA scientists skeptical of whether Voyager 1 has truly entered interstellar space.

The heliosphere -- which is a bubble of charged particles surrounding our solar system and is dominated by the sun -- has a heliopause transition zone that leads to interstellar space. This is a zone with unknown properties, but many believe that the loss of solar particles and the remainder of galactic particles is a sign that the craft has left the heliopause transition zone. A different direction in the local magnetic field is also a key sign.

So how are there no solar particles, but the magnetic field's direction hasn't changed? Scientists believe Voyager 1 has entered a heliosheath depletion region, where it remains in a section of the heliosphere.

However, the UMD team's model of the outer edge of the solar system may have a new solution that points to Voyager 1's exit of the heliosphere entirely.

According to the UMD researchers, magnetic reconnection -- which is the breaking and reconfiguring of oppositely-directed magnetic field lines -- is the explanation. The team said that the heliopause isn't the split between inside and outside of the solar system. Rather, it's a "porous" structure that creates a set of magnetic spots, which are self-contained and appear in a magnetic field due to a "fundamental instability." Galactic plasma and cosmic rays are allowed to mix with solar particles through the use of reconnected field lines.

Reconnection sites issue slopes in the magnetic field, where solar particles are known to decrease and galactic particles increase. However, the magnetic field direction doesn't change, and this is how UMD researchers explain what NASA is finding.

UMD isn't alone in its way of thinking. In March of this year, a new study conducted by researchers at New Mexico State University in Las Cruces suggested that Voyager 1 exited the heliosphere on the edge of the solar system in 2012 as well. These findings were based on the fact that levels of anomalous cosmic rays (which are in the heliosphere) dropped to 1 percent from previous levels while levels of galactic cosmic rays (which are outside the solar system) increased to twice their previous levels during late August 2012. This was the highest these levels have ever been.

The Voyager 1 is a NASA space probe that was launched in 1977 to study the outer solar system.

The Voyagers actually weren't the first spacecraft to visit the outer planets. Pioneer 10 was the first to visit Jupiter, while Pioneer 11 did a flyby of both Jupiter and Saturn (though the planetary alignment at the time meant that it had to cross back across the entire solar system to get to Saturn). The Voyagers were much more capable and (more importantly in the public's eye) had better cameras. But Pioneer set the stage and gave researchers an inkling of what questions to ask Voyager to answer.

The Russians mostly concentrated on Venus. It's a bit counterintuitive, but visiting the inner planets takes energy too. There's nothing to grab onto and slow yourself down in space, so "falling" towards the sun takes energy just like pulling away from it. It's the reason there have only been two missions to Mercury - too much delta-v required for what's considered a rather uninteresting planet.

It wasn't their fault Venus turned out to be completely covered with thick clouds making it uninteresting to the public. You can't take a vista-like photo on Venus like you can on Mars. Prior to the space program, popular opinion was that Venus was Earth's sister planet and most likely to harbor life. In the old sci-fi stories, the aliens are almost always from Venus. So it was natural for the Russians to pick it as their first choice.

The heat and high pressure on Venus (850 F, over 90 atmospheres) actually makes it much more difficult to build a Venus lander than a Mars (or Titan) lander. They needed to mount the camera behind a window made of diamond. (OTOH the high pressure meant they only needed a drogue chute for early re-entry. For the landing stage, there was no parachute. The thick atmosphere generated enough air resistance to slow the spacecraft down for a soft landing.)